use the js-sdk where the hashed rtcSessionIdeintity is already part of

the event (no need to compute it in the encryption manager)

src/e2ee/matrixKeyProvider.ts

@@ -10,7 +10,6 @@ import {
   type MatrixRTCSession,
   MatrixRTCSessionEvent,
 } from "matrix-js-sdk/lib/matrixrtc";
-import { type CallMembershipIdentityParts } from "matrix-js-sdk/lib/matrixrtc/EncryptionManager";
 import { logger as rootLogger } from "matrix-js-sdk/lib/logger";
 const logger = rootLogger.getChild("[MatrixKeyProvider]");
 
@@ -27,10 +26,6 @@ export class MatrixKeyProvider extends BaseKeyProvider {
         MatrixRTCSessionEvent.EncryptionKeyChanged,
         this.onEncryptionKeyChanged,
       );
-      this.rtcSession.off(
-        MatrixRTCSessionEvent.MembershipsChanged,
-        this.onMembershipsChanged,
-      );
     }
 
     this.rtcSession = rtcSession;
@@ -39,63 +34,17 @@ export class MatrixKeyProvider extends BaseKeyProvider {
       MatrixRTCSessionEvent.EncryptionKeyChanged,
       this.onEncryptionKeyChanged,
     );
-    this.rtcSession.on(
-      MatrixRTCSessionEvent.MembershipsChanged,
-      this.onMembershipsChanged,
-    );
 
     // The new session could be aware of keys of which the old session wasn't,
     // so emit key changed events
     this.rtcSession.reemitEncryptionKeys();
   }
 
-  private keyCache = new Array<{
-    membership: CallMembershipIdentityParts;
-    encryptionKey: Uint8Array;
-    encryptionKeyIndex: number;
-  }>();
-
-  private onMembershipsChanged = (): void => {
-    const duplicatedArray = this.keyCache;
-    // Reset key cache first. It will get repopulated when calling `onEncryptionKeyChanged`
-    this.keyCache = [];
-    let next = duplicatedArray.pop();
-    while (next !== undefined) {
-      logger.debug(
-        "[KeyCache] remove key event from the cache and try adding it again. For membership: ",
-        next.membership,
-      );
-      this.onEncryptionKeyChanged(
-        next.encryptionKey,
-        next.encryptionKeyIndex,
-        next.membership,
-      );
-      next = duplicatedArray.pop();
-    }
-  };
-
   private onEncryptionKeyChanged = (
     encryptionKey: Uint8Array,
     encryptionKeyIndex: number,
-    membership: CallMembershipIdentityParts,
+    rtcBackendIdentity: string,
   ): void => {
-    // This is the only way we can get the kind of the membership event we just received the key for.
-    // best case we want to recompute this once the memberships change (you can receive the key before the participant...)
-    const membershipFull = this.rtcSession?.memberships.find(
-      (m) =>
-        m.userId === membership.userId &&
-        m.deviceId === membership.deviceId &&
-        m.memberId === membership.memberId,
-    );
-    if (!membershipFull) {
-      logger.debug(
-        "[KeyCache] Added key event to the cache because we do not have a membership for it (yet): ",
-        membership,
-      );
-      this.keyCache.push({ membership, encryptionKey, encryptionKeyIndex });
-      return;
-    }
-
     crypto.subtle
       .importKey("raw", encryptionKey, "HKDF", false, [
         "deriveBits",
@@ -105,7 +54,7 @@ export class MatrixKeyProvider extends BaseKeyProvider {
         (keyMaterial) => {
           this.onSetEncryptionKey(
             keyMaterial,
-            membershipFull.rtcBackendIdentity,
+            rtcBackendIdentity,
             encryptionKeyIndex,
           );